fix flaky test with timestamp (elastic#195681)

## Summary

It fixes the flaky test raised on elastic#195634 by adding the possibility to
pass the timestamp to the function. That helps to eliminate flakiness,
by passing the same `currentTimestamp` to both the test and the
function. Also, it's a simpler approach that doesn't require mocking
global objects or using Jest's fake timers, keeping your test
straightforward and easy to understand.

(cherry picked from commit b51ba0a)

x-pack/plugins/cloud_security_posture/public/pages/vulnerabilities/utils/create_detection_rule_from_vulnerability.test.ts

@@ -89,7 +89,7 @@ describe('CreateDetectionRuleFromVulnerability', () => {
       } as Vulnerability;
       const currentTimestamp = new Date().toISOString();
 
-      const query = generateVulnerabilitiesRuleQuery(mockVulnerability);
+      const query = generateVulnerabilitiesRuleQuery(mockVulnerability, currentTimestamp);
       expect(query).toEqual(
         `vulnerability.id: "CVE-2024-00005" AND event.ingested >= "${currentTimestamp}"`
       );

x-pack/plugins/cloud_security_posture/public/pages/vulnerabilities/utils/create_detection_rule_from_vulnerability.ts

@@ -53,10 +53,11 @@ export const getVulnerabilityRuleName = (vulnerability: Vulnerability) => {
   });
 };
 
-export const generateVulnerabilitiesRuleQuery = (vulnerability: Vulnerability) => {
-  const currentTimestamp = new Date().toISOString();
-
-  return `vulnerability.id: "${vulnerability.id}" AND event.ingested >= "${currentTimestamp}"`;
+export const generateVulnerabilitiesRuleQuery = (
+  vulnerability: Vulnerability,
+  startTimestamp = new Date().toISOString()
+) => {
+  return `vulnerability.id: "${vulnerability.id}" AND event.ingested >= "${startTimestamp}"`;
 };
 
 const CSP_RULE_TAG = 'Cloud Security';